Roller-band device with over-center means

ABSTRACT

A roller-band device including a housing, a roller and a band encircling the roller and having its ends attached to the housing in tension. A portion of the band acts as a leaf spring to provide over-center action of the roller between two end positions. Means is provided for adjusting the spring force of the over-center means and thus the force required to move the roller between the two end positions.

United States Patent Bluem 51 Mar.21, 1972 [54] ROLLER-BAND DEVICE WITH OVER- CENTER MEANS [73] Assignee: Kroy Industries, Inc., Minneapolis, Minn.

OTHER PUBLICATIONS Wilkes, D. F., Rolamite: A New Design Concept, Publ. l2- 67 Sadia Laboratories, pp. 102- [03 Primary ExaminerDavid Smith, Jr. Attorney-Frederick E. Lange, William C. Babcock and David 22 Filed: Feb. 9, 1910 Fmnek [21] A l. No.2 9 606 pp 57 ABSTRACT [52] us. Cl ..200/67 DA, 74/89, 306/6 A r ll n device including a i g, a roller n a n [51] Int. Cl. ..H0lh 13/48 encircling the roller and having its ends attached to the hous- Field of Search 67 306/6 ing in tension. A portion of the band acts as a leaf spring to provide over-center action of the roller between two end posi- [56] References Cited tions. Means is provided for adjusting the spring force of the UNITED STATES PATENTS over-center means and thus the force required to move the roller between the two end positions. 2,947,185 8/l960 Ziegler ..74/89.2 3,488,098 1/1970 Sobczak ..308/6 12 Claims, 3 Drawing Figures p 10 54 55 .lZc

jzzz -L 26 24 25 PATENTEDMARZ] I972 3,651,291

INVENTOR. G4 a e 84 UEM ATTOEAIEV BACKGROUND OF THE INVENTION Roller-band devices have become relatively well-known in the past few years, particularly since disclosure to the public of the work done by Donald Wilkes on so-called Rolamite" devices. These devices are shown, for example, in US. Pat. No. 3,452,l75 and 3,452,309, both issued to Donald Wilkes and assigned to the United States of America. Rolamite devices utilize a flexible band formed into a generally S- shaped configuration with two rollers, one disposed on either side of the band and in one of the loops of the S-shape. These devices provide a relatively low friction mechanism which, it has been suggested, may be utilized to provide a multitude of switching and other functions in response to a relatively small input force.

Another form of roller-band device utilizing a single roller has been disclosed, for example, in the US. Pat. No. 3,167,962 issued to Dominick Scotto and in US. Pat. No. 3,488,098 issued to Bernard Sobczak. In this type of device a single roller is utilized with a band having complimentary cutaway portions so that a tongue portion wraps around the roller and extends through a space between the pair of spaced leg portions and the ends of the band extend generally in opposite directions from the roller. They have the obvious advantage of being simpler than the Rolamite device in that they use a single roller and also that there is much less stress on the band since it is not doubled back against itself as is the case in the S-shaped band of the Rolamite devices.

While roller-band devices of the types referred to above have become known and have been suggested as being capable of use in many applications, they have not actually found much commercial use. There has been a need for simple, easy to manufacture, applications of these devices which can be readily used for electrical switches or the like.

BRIEF SUMMARY OF INVENTION This invention provides a roller-band device with overcenter means for moving the roller and band between two and positions. The band encircles the roller and has its ends extending in opposite directions from the band and connected to a support under tension. The support defines two end positions for the roller and band and over-center means operating on the roller band intermediate these end portions renders the device unstable in any but these two end positions. Preferably the over-center action is provided by a portion of the band itself which acts as an over-center spring having its free end cooperating with a portion of the housing for the device. This spring preferably acts as a leaf spring deformed into a generally S-shaped configuration with its connection to the housing being approximately equidistance from the two end positions of the roller and band. Adjustable means may be provided for the adjusting of the free end of the spring toward and away from the roller, thereby varying the amount of distortion of the spring and the amount of force required to cause the roller to pass through the over-cener position.

The over-cener roller-band device is illustrated in connection with a simple electrical switching arrangement but it may be utilized in various types of such switching arrangements and may also be used for performing other functions such as valving fluids or the like.

An object of the invention is to provide a roller-band device with over-center means rendering the device unstable in any but two end positions.

Another object of the invention is to provide a rollerband device of the type referred to above wherein the band itself has a portion which acts as an over-center spring for the device.

Still another object of the invention is to provide a rollerband device with over-center means as described above, in-

eluding adjustable means for varying the force required to move the roller and band through the over-cener position.

These and other objects will be come apparent upon reading the detailed description of the invention which follows.

DESCRIPTION OF DRAWING FIG. I is a perspective view of a band utilized in connection with a roller-band device of this invention.

FIG. 2 is a schematic cross-sectional view of a roller-band device constructed according to this invention and disclosing the roller in one of its end positions.

FIG. 3 is also a schematic cros-sectional view, generally similar to FIG. 2, but disclosing the roller in its other end position.

DETAILED DESCRIPTION Referring to the drawing numeral 10 generally designates a roller-band device constructed according to this invention. The device includes a generally box-shaped electrically insulative housing 11 which has a cover 12. Disposed within the housing is a band 13 which encircles a cylindrical roller 14. As seen in FIG. 1, band 13 has complimentary cutaway and solid portions so that it can cross over itself and extend in opposite directions from the roller without engaging itself in so doing. As seen in FIG. 1, the band has one portion which includes a pair of spaced legs 14 and 15 and a tongue portion 16 joined to the leg portion by a common portion 17. Extending from common portions 17, and generally from right angles thereto, is an extending spring portion 18. Opposite ends of band 13 are adapted for connection to housing 1 1.

Band 13 encircles roller 14 with tongue 16 extending between the spaced legs 14 and 15. Opposite ends of the band are connected to the base of housing 11 by appropriate means such as screws 20 and the band is held in tension so that it rather tightly encircles roller 14. Roller 14 is movable with the band along the surface of the base of housing 1 1 generally in a direction normal to the axis of the roller. The end positions of the travel of the roller are determined by a pair of abutment members 21 and 22 extending inwardly from the ends of the housing and into the path of the roller and band. The roller and band may be used to perform an electrical switching function, a valving function, or the like. By way of example, abutment member 21 is disclosed as including an electrical contact 23 on its inner end adapted for engagement by the roller and band in one of its end positions and having an electrical conductor 24 connected thereto and extending outward from the housing for connection into an electrical circuit. Abutment 22 has an en electrical contact 25 disposed in the path of the roller and band and is connected to an electrical conductor 26 which extends externally from the housing. Preferably band 13 is itself electrically conductive and it has one end extending from the housing as an electrical conductor 27 which also may be connected into an electric circuit.

Member 18 which extends from the portion 17 intermediate the tongue and the legs has its remote end disposed in a notch or slot 30 in the housing, thus providing an operable connection between member 218 and the housing. As seen in FIGS. 2 and 3, this causes member 18 to be distorted generally into an S-shaped configuration. Notch 30 is preferably disposed approximately equidistance between the two end positions of the roller and band and defines an overcenter position. Roller 14 is biased either to the end position disclosed in FIG. 2 or the one disclosed in FIG. 3 and is unstable in all other positions.

Obviously, the amount of force which is required to cause the roller to move through the overcenter position will be dependent upon the spring force exerted by member 18. This spring force may be varied by varying the thickness or the rigidity, thus varying the spring constant of member 18. It may also be varied by changing the position of the free end, changing the effective length, of member 18. It may be desirable to make the spring force by member 18 selectively adjustable. Therefore, FIGS. 2 and 3 disclose schematically means for accomplishing this adjustment. Here a screw 32 is threaded into a cooperating threaded opening in cover 12 and can be rotated from the outside of the housing to advance it toward or away from the inside of the housing. Slot 30 is formed in a piece 33 which is separate from cover 12 and is movable with respect thereto generally along the same axis as screw 32.

Screw 32 is connected to member 33 by a swivel connection or the like so that the screw may be rotated while member 33 i is simply moved toward or away from the roller. This may be accomplished, for example, by a simple ball and socket connection utilizing a ball 34.

Screw 32 may be selectively turned into or away from the opening of the housing thus varying the distortion of spring member 18 and the force exerted thereby. This adjustment will determine to the amount of external force which is required to cause the roller to pass through its overcenter position. The switch device may be used as a G-switch wherein no external connection for applying force is required but rather the roller itself acts as a mass responsive to a G-force. If desired, the device may respond to other types of forces, such as magnetic forces or the like or it may be activated by the application of a force through a mechanical linkage. In any of these arrangements the overcenter feature will cause the roller to be positively displaced at one end position or the other with the roller moving through its center position only in response to a force predetermined by the amount of force applied by spring member 18.

While member 18 acts as a leaf spring, it will be appreciated that other types of overcenter spring arrangements may be utilized in this type of device. The leaf spring arrangement disclosed is, however, probably the simplest arrangement and is particularly because member 18 can be made an integral part of the rest of the band.

The operation of the device will perhaps be apparent and will therefore be described only very briefly. With the roller in the position disclosed in FIG. 2, an electrical circuit is completed through conductor 26, contact 25, band 13, and electrical conductor 27. When the roller is subjected to sufficient force urging it to the left (as seen in FIGS. 2 and 3) to overcome the force exerted by spring member 18, it moves through the overcenter position to the position disclosed in FIG. 3. Here the roller and band engage contact 23 on stop member 21 and a circuit is completed through electrical conductor 24, contact 23, band 13, and electrical conductor 27. Obviously, the roller will again move to the right upon the application of sufficient force in that direction to cause it to move through the overcenter position.

The structure described provides a simple and easily constructed roller-band device particularly adaptable for use in switching electrical current and also adaptable for fluid valving or the like. A particular embodiment as been disclosed as by way of example. Since many variations and modifications may become apparent to those skilled in the art in view of the disclosure herein without departing from the spirit of the invention, it is to be understood that this disclosure is made by way of example and not by way of limitation. The invention is to be limited solely by the scope of the appended claims.

The embodiments of the invention in which an exclusive property or right is claimed are defined as followed:

1. A roller-band device comprising frame means, a roller, a flexible band encircling said roller and having its ends extending from said roller generally in opposite directions, means connecting the ends of the band to said frame means, said roller and band being movable together back and forth along said frame means, means defining first and second end positions of said roller on said frame means, and over-center means acting upon said roller and hand between said end positions including a relatively non-extensible member having one end connected to said roller and the other end connected to said frame means such as that movement of said roller causes said member to flex.

2. The device of claim 1, wherein said relatively non-extensible member is connected to said frame means at a point intermediate between the end positions of said roller.

3. The device of claim 2 wherein said relatively non-extensible member is a leaf spring member which is flexed into an S- shaped configuration.

4. The device of claim 3 wherein said relatively non-extensible member flexes from a generally S-shaped configuration to a generally inverted S-shaped configuration as said roller moved from one of its end positions to the other.

5. A roller-band device comprising frame means, a roller, a flexible band encircling said roller and having its ends extending from said roller generally in opposite directions, means connecting the ends of the band to said frame means, said roller and band being movable together back and forth along said frame means, means defining first and second end positions of said roller on said frame means, and over-center means including a portion of said band operably connected to said frame means and acting as an overcenter spring urging said roller to one of its end positions.

6. The device of claim 5 wherein said portion of said band comprising a portion thereof extending from the band and acting as a leaf spring which is deformed when it is connected to the frame means.

7. The device of claim 6 wherein said portion of the band which acts as a leaf spring is deformed generally into an S- shaped and has its free end connected to said frame means at a point generally equidistance from the end positions of said roller.

8. The device of claim 5 wherein said portion of said band is operably connected to said frame means at a point substantially equidistance between the two end positions of said roller.

9. The device of claim 5 further including means for adjusting the spring force of said overcenter means.

10. The device of claim 7 further including means movable on said frame means for moving the operable connection between said frame means and said portion of said band toward and away from said roller to vary the spring force of said over-center device.

11. The device of claim 1 wherein said band comprises a first portion including a pair of said spaced leg members and a second portion comprising a tongue portion having a width less than the space between said legs, said band encircling said roller with the tongue extending between said legs and said legs extending in one direction therefrom and the tongue portion in the other, and wherein said portion acting as an overcenter spring comprises a leaf spring member formed from a part of said band and extending generally normal thereto at a point near the connection between said legs and said tongue portion.

12. The device of claim 1 further including fixed electrical contact means mounted on said frame means and adapted from engagement by one of said roller and band in at least one of said end positions, and said roller and band providing electrically conductive means adapted to complete an electrical circuit when in engagement with said fixed contact means. 

1. A roller-band device comprising frame means, a roller, a flexible band encircling said roller and having its ends extending from said roller generally in opposite directions, means connecting the ends of the band to said frame means, said roller and band being movable together back and forth along said frame means, means defining first and second end positions of said roller on said frame means, and over-center means acting upon said roller and band between said end positions including a relatively non-extensible member having one end connected to said roller and the other end connected to said frame means such as that movement of said roller causes said member to flex.
 2. The device of claim 1, wherein said relatively non-extensible member is connected to said frame means at a point intermediate between the end positions of said roller.
 3. The device of claim 2 wherein said relatively non-extensible member is a leaf spring member which is flexed into an S-shaped configuration.
 4. The device of claim 3 wherein said relatively non-extensible member flexes from a generally S-shaped configuration to a generally inverted S-shaped configuration as said roller moved from one of its end positions to the other.
 5. A roller-band device comprising frame means, a roller, a flexible band encircling said roller and having its ends extending from said roller generally in opposite directions, means connecting the ends of the band to said frame means, said roller and band being movable together back and forth along said frame means, means defining first and second end positions of said roller on said frame means, and over-center means including a portion of said band operably connected to said frame means and acting as an overcenter spring urging said roller to one of its end positions.
 6. The device of claim 5 wherein said portion of said band comprising a portion thereof extending from the band and acting as a leaf spring which is deformed when it is connected to the frame means.
 7. The device of claim 6 wherein said portion of the band which acts as a leaf spring is deformed generally into an S-shaped and has its free end connected to said frame means at a point generally equidistance from the end positions of said roller.
 8. The device of claim 5 wherein said portion of said band is operably connected to said frame means at a point substantially equidistance between the two end positions of said roller.
 9. The device of claim 5 further including means for adjusting the spring force of said overcenter means.
 10. The device of claim 7 further including means movable on said frame means for moving the operable connection between said frame means and said portion of said band toward and away from said roller to vary the spring force of said over-center device.
 11. The device of claim 1 wherein said band comprises a first portion including a pair of said spaced leg members and a second portion comprising a tongue portion having a width less than the space between said legs, said band encircling said roller with the tongue extending between said legs and said legs extending in one direction therefrom and the tongue portion in the other, and wherein said portion acting as an overcenter spring comprises a leaf spring member formed from a part of said band and extending generally normal thereto at a point near the connection between said legs and said tongue portion.
 12. The device of claim 1 further including fixed electrical contact means mounted on said frame mEans and adapted from engagement by one of said roller and band in at least one of said end positions, and said roller and band providing electrically conductive means adapted to complete an electrical circuit when in engagement with said fixed contact means. 